JPH0875579A - Pressure measuring instrument, and mold for casting with the instrument - Google Patents

Abstract

PURPOSE: To obtain a separate pressure measuring instrument from a mold for its easing mounting and removal by laying out a rod for transferring the amount of deflection on the reverse side of a deflection plate part which is formed on the surface of a block for a gauge, laying out a plate for measuring the amount of deflection where one portion is supported by a retention tool at the rear side of the block while the transfer rod is being pressed, and applying a strain gauge to the measurement plate. CONSTITUTION: The tip part of a rod 5 for transferring the amount of deflection is laid out at the reverse side of the center of a deflection plate part 3 while the tip is in contact with the rod 5 and a rear edge surface is provided while the center part of a plate 6 for measuring the amount of deflection in flat-plate shape is pressed. A cylindrical block 7 is loaded into a hole 4 and is brought into contact with a thick part 3b of the plate part 3. A bush 15 is provided at the center of the shaft center of the block 7, thus enabling the transfer rod 6 to be slid freely. One-edge side of the plate 6 for measuring the amount of deflection is fixed to a cylindrical member 9 in cantilever shape by a press plate 11 and a bolt 12. A strain gauge 13 is applied to the root side on the reverse side of the measurement plate 6. A strain gauge 14 for compensating temperature is applied to the reverse side at the tip side of the measurement plate 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure measuring device and a pressure measuring device for measuring the pressure in a metal mold when a light metal alloy such as an aluminum alloy or a magnesium alloy is pressure-cast with a metal mold. The present invention relates to a provided casting mold.

[0002]

2. Description of the Related Art Conventionally, when casting a light metal alloy such as an aluminum alloy, in general, in order to reduce shrinkage cavities, high pressure is applied from the time when the molten metal is cast into the mold until the solidification is completed. The method of continuing to pressurize has been adopted. In particular,
When high quality such as pressure resistance and high strength is required such as automobile parts, the above-mentioned high pressure casting method is often used. In this case, the magnitude of the pressure applied to the molten metal filling each part of the product greatly affects the quality of the product. For this reason, conventionally, the pressure of the molten metal was sometimes measured and used to control the casting conditions. In that case, a strain gauge was set on the back of the extrusion pin and the pressure of the molten metal was measured. Was.

As described above, when the strain gauge is set on the back of the extrusion pin, there is a problem that the measured value is not accurate due to the sliding resistance and frictional force of the extrusion pin with respect to the mold or the like.
This sliding resistance increases due to seizure, galling, etc. as casting is continued. Incidentally, JP-A-6-19054
When the pressure is applied in pulses as described in No. 3,
In particular, this issue is greatly highlighted. That is, when the pressure applied to the extrusion pin changes from a decrease to an increase, the extrusion pin remains stationary until the increase exceeds the static friction force. Conversely, when the pressure changes from increasing to decreasing, the push pin remains stationary until the amount of decrease exceeds the static friction force. Therefore, if the pressure fluctuation is smaller than the static frictional force, the push pin may not move at all and the pressure may not be measured in some cases.

Therefore, in order to eliminate such drawbacks, the applicant company has an in-mold pressure measuring device having a structure in which a part of the part of the mold facing the cavity is bent by a pressing force. Without receiving sliding resistance as in the past,
The pressure of the molten metal can be measured accurately. And, for example, Japanese Patent Application No. 5-116014 and Japanese Patent Application No. 5-2795.
As described in No. 11, a bending plate is provided on a part of the surface of the mold on the cavity side, and a bending amount transmitting rod whose tip is in contact with the back side of the central part of the bending plate is arranged to obtain the bending amount. For example, a disk-shaped flexure amount measurement plate is placed on the rear end surface of the transmission rod in a pressed state, and the outer periphery of the flexure amount measurement plate is supported by a holder attached to the die, and the flat surface part of the flexure amount measurement plate is supported. A strain gauge was attached.

[0005]

However, in these methods and devices, since a disk-shaped bending amount measuring plate is used and the entire circumference of the bending amount measuring plate is supported by simple support, strain Measurement of strain and deflection with a gauge, and
Accompanying this, it has been relatively difficult to accurately obtain the pressure in the die that is calculated and obtained.

That is, in the conventional type, as shown in FIG. 5, a strain gauge 31 is attached to the back side of the central portion of a disc-shaped flexure amount measuring plate 30, and a mold not shown in FIG. Bending amount transmission rod 32 whose tip is in contact with the back side of the portion that is made to bend by the pressure applied to the portion facing the cavity
Since the rear end is brought into contact with the central portion of the surface of the flexure amount measuring plate 30, the flexure amount measuring plate 30 is curved, for example, as shown by the solid line in FIG. 5, depending on the magnitude of the pressing force. , 2
It bends as shown by the dashed line.

In this case, the bending amounts are δ ₁ and δ ₂ , respectively, and the distances from the corners of the supporting member 33 to the ends of the bending amount measuring plate 30 are a and b, respectively. It gets shorter. In this way, since the support point moves with the change in the amount of bending, the strain change is not linear.

Further, since the flexure amount measuring plate 30 is a circular plate and is simply supported, its core may be displaced, which may result in failure to obtain a correct measured value. On the other hand, in the above-mentioned conventional method and device, the influence of the temperature change of the mold on the strain gauge was not taken into consideration. That is, the effect of temperature on the strain gauge resistance value was not taken into consideration.

Further, in the conventional one, the deflection amount transmission rod 32
Of the tip of the abutting part of the back surface of the flexible plate of the mold,
Also, the bending amount measuring plate 30 at the rear end of the bending amount transmission rod 32
Since the portion in contact with the flat surface has a predetermined width, when the bending plate portion of the mold or the bending amount measuring plate 30 bends, the bending amount transmitting rod 32 has a front end portion or a rear end portion. The contact position with and sometimes changed.

Further, for example, as shown in FIG. 6, when the acting point of the force F acting on the bending plate portion 34 of the mold as the measuring portion is different from the position of the bending amount transmission rod 32, The flexible plate portion 34 is provided only on one corner 32a of the tip portion of the quantity transmission rod 32.
It becomes difficult to make accurate measurements. Due to various reasons as described above, it has been difficult or difficult to obtain an accurate in-mold pressure in the past.

Further, in the above-mentioned conventional one, the flexible plate portion 34
It was an embodiment in which itself was completely integrated with the portion of the mold facing the cavity. Therefore, in this case, if a problem occurs in the flexible plate portion 34, the cavity surface itself of the mold must be repaired, which is inconvenient and requires a large number of steps and costs.

[0012]

The present invention has been made in order to solve such a problem, and a pressure measuring device has a tip on the back surface of a flexible plate portion formed on a part of the front surface of the block. The deflection amount transmitting rods that are in contact with each other are arranged, and the deflection amount measuring plate partially supported by the holder on the rear side of the block is placed against the rear end face of the deflection amount transmitting rod, and the plane of the deflection amount measuring plate is arranged. It was constructed by attaching a strain gauge to the part. In addition, the deflection amount measuring plate provided in the block is a flat plate, and one end of this plate-shaped deflection amount measuring plate is fixed to the holder in a cantilever manner, and the rear end face of the deflection amount transmitting rod measures the deflection amount. The strain gauge was attached to the deflection amount measurement plate at the base side of the position where it is in contact with the plate.

Further, a temperature compensating strain gauge is attached to the flexure amount measuring plate at the tip end side of the position where the rear end surface of the flexure amount transmitting rod is in contact with the flexure amount measuring plate. In addition, the center of the tip of the bending amount transmitting rod, which is in contact with the back surface of the central portion of the bending plate, is tapered. In addition, the central portion of the rear end of the deflection amount transmission rod, which is in contact with the deflection amount measurement plate, is tapered. Further, these pressure measuring devices are embedded in the stepped holes provided on the cavity side of the mold, and the surface of the block of the pressure measuring device constitutes a part of the surface of the mold cavity. A casting mold equipped with a device was used.

[0014]

[Function] Since the pressure measuring device is provided separately from the mold by using the block, it can be manufactured separately and incorporated into the mold, and if a problem occurs in the pressure measuring device, this It is convenient because the pressure measuring device can be removed from the mold and repaired.

When a mold having the above-mentioned pressure measuring device attached to the cavity surface is used and molten metal or the like is injected into the cavity of the mold to generate pressure in the cavity, the bending plate portion bends, and the bending amount transmitting rod Is pressed and the cantilever-supported plate-shaped deflection amount measuring plate bends, and the strain amount is measured with a strain gauge. The amount of strain is calculated by a computer, etc., and the pressure inside the mold is determined.

As an example of the pressure measuring device, the bending amount measuring plate is cantilevered and fixed, and the strain gauge is attached to the base side of the bending amount measuring plate. In that case, the fulcrum moves. No, the strain change appears linearly and the strain can be easily measured. Also, since the temperature compensation strain gauge is attached to the non-deformation part on the tip side of the deflection amount measurement plate, it changes depending on the temperature change. Only the elongation of the flexure amount measuring plate can be accurately measured, and the temperature can be compensated.

Further, if a bending amount transmitting rod having a tapered front end portion and a rear end portion is used, the contact point with the bending plate portion or the bending amount measuring plate may change or shift. No, there is always good measurement.

[0018]

1 and 2 show one embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a part of a bottom view, and FIG.
-A line enlarged view. 1 is a part of the mold, 1a is a cavity which is a molten metal casting space in the mold 1, 2 is a block fitted in a part of the surface of the mold 1 on the side of the cavity 1a, 3 is the cavity 1a side of the block 2 It is a relatively thin circular flexible plate portion provided on a part of the surface of the flexible plate portion 3, and a relatively deep hole 4 is provided from the rear side behind the flexible plate portion 3.

On the back side of the central portion of the flexure plate portion 3, a round bar-shaped flexure amount transmission rod 5 is disposed so as to be in contact with it, and a relatively thin flat plate-like flexure amount is provided on the rear end face of the flexure amount transmission rod 5. The measurement plate 6 was arranged in a state where the central portion thereof was pressed or abutted. It should be noted that the contact point with the flexure amount measuring plate 6 or the measurement 0 point may be delicately shifted due to the thermal expansion of the flexure amount transmitting rod 5, for example Be.
When the bending amount measuring plate 6 made of a Cu plate reaches a high temperature of 200 ° C. or higher, the bending amount measuring plate 6 and strain gauges 13 and 1 to be described later are provided.
In consideration of the tendency of No. 4 to deteriorate, the flexure amount transmission rod 5 is made of a material having a small thermal expansion coefficient and a small thermal conductivity, for example, Si ₃ N ₄ .

A stepped cylindrical block 7 is inserted into the hole 4, and the block 7 is attached to the block 2 with a screw 8 in a state where the tip end surface of the block 7 is in contact with the back surface of the flexible plate 3. Installed on the rear side.

The flexible plate portion 3 provided on the block 2 is composed of a relatively thin circular portion 3a provided at the center and a relatively thick circular portion 3b around the circular portion 3a. Then, the ring-shaped protrusion 7a provided at the tip of the block 7 was brought into contact with the back surface of the thick portion 3b. The reason why such a shape is adopted is that the flexible plate portion 3 is made to easily vibrate, and the molten metal cast in the cavity 2 is vibrated so that the metal structure at the time of solidification becomes better.

A bush 15 is provided at the center of the axis of the block 7.
Was attached, and the deflection transmission rod 5 was guided slidably in the axial direction. By doing so, the position of the bending amount transmitting rod 5 does not shift, and the tip portion 5a of the bending amount transmitting rod 5 is always in contact with the center position of the thin portion 3a.
The tip portion 5a of the deflection amount transmission rod 5 is formed into a spherical shape, and the deflection plate portion 3
Even if force is eccentrically applied to the tip, the tip 5a is always set to one point. On the other hand, the rear end portion 5b of the deflection amount transmitting rod 5 is formed into a conical shape or a spherical shape so that point contact is maintained in the same manner.

A tubular member 9 was screwed to the rear end of the circular hole provided in the center of the block 7. In the member 9,
A hole 10 having a convex cross-section is provided so as to pass through the inside thereof in the vertical direction. Further, the member 9 on the side without the protruding hole 10a is
Part of it was cut with a constant width to reduce the height.

One end of a flat plate-shaped bending amount measuring plate 6 was cantilevered to the processed surface with a holding plate 11 and bolts 12. The tip portion of the deflection amount measuring plate 6 extends into the protrusion-shaped hole 10a, and the side surface of the tip portion is provided so as not to come into contact with the inner surface of the hole 10a and to be able to move up and down freely. Here, the block 7, the member 9, the bolt 12 and the like constitute a holder attached to the mold 1 for cantilever supporting one end of the deflection amount measuring plate 6.

A commercially available strain gauge 13 is attached to the base side of the back surface of the deflection amount measuring plate 6, and the strain gauge 10 is
It is connected to a strain amount measuring device body (not shown). In this device, since the bending plate portion 3 is connected to the bending amount measuring plate 6 through the bending amount transmitting rod 5, the bending amount of the bending amount measuring plate 6 is bent in proportion to the magnitude of pressure. It corresponds to the amount of strain of the plate portion 3. The thickness of the flexible plate portion 3, the inner diameters of the block 7 and the member 9, and the contact position between the rear end portion of the flexible amount transmission rod 5 and the flexible amount measuring plate 6 to the base portion of the flexible amount measuring plate 6 are measured. In consideration of the distance, the size of the flexure amount measuring plate, etc., the pressure acting on the flexure plate portion 3 can be converted from the strain amount of the flexure amount measuring plate 6 to be always immediately and accurately obtained. The pressure obtained by the conversion can be displayed as a numerical value or can be displayed on a monitor in a graph to know the pressure fluctuation state.

A strain gauge 14 for temperature compensation was attached to the back surface of the bending amount measuring plate 6 on the front end side. In the cantilevered flexure amount measuring plate 6, the tip end side of the contact point of the flexure amount transmitting rod 5 is a non-deformable portion that is not deformed even when pushed by the flexure amount transmitting rod 5. So the distortion here is
It is only the strain due to the bending amount measuring plate 6 expanding and contracting due to the temperature change. Therefore, on the basis of the strain measured by the temperature compensating strain gauge 14, temperature change is obtained by calculation, or temperature compensation is performed when the mold internal pressure is calculated, and the mold internal pressure is obtained more accurately. be able to.

When the strain generated in the strain gauge 13 or in the strain gauge 13 and the temperature compensating strain gauge 14 is obtained, a well-known Wheatstone bridge circuit is used and it is recognized as a change in electric resistance. If this Wheatstone bridge circuit is used, it can be applied even if there are multiple strain gauges.
For example, when two strain gauges 13 are used, they can be arranged on the deflection amount measuring plate 6 or can be placed on both front and back surfaces.

Also in the case of the temperature compensating strain gauge 14, the change amount of the resistance value caused by the temperature change is detected. In this case, the temperature compensating strain gauge 14 functions as a dummy gauge, and strain due to the applied pressure is not picked up. In this case, a bridge circuit known as an active dummy method can be used.

In the above embodiment, the strain gauge 1
Although the example in which 3, 14 are attached to the back surface of the deflection amount measuring plate 6 is shown, this may be attached to the front surface of the deflection amount measuring plate 6.

FIG. 3 is a vertical sectional view showing another embodiment of the present invention. 3, the same parts as those in FIG. 1 are designated by the same reference numerals as those in FIG. 1, and the description thereof will be omitted. In Figure 1,
The block 2 was fitted into the mold 1 from the cavity 1a side, but in FIG. 3, the block 2 was fitted from the back side of the mold 1.

In FIG. 3, the block 2 having the flexible plate portion 3 on the front surface side is fixed to the block 7 by a bolt 16 inserted through the block 7 from the back surface side. At this time, the tubular member 9 to which the bending amount measuring plate 6 is attached is also integrally fixed to the back surface side of the block 7 by the bolt 16 at the same time. The block 7 was fixed to the mold 1 with bolts 17 from the back side.

The deflection amount transmitting rod 5 does not have the same cross section over the entire length, and the large diameter portion 5c is provided only in the portions near the both ends in the block 7, and the other portions are the small diameter portions 5d. Only the large diameter portion 5c is blocked by the block 7 Sliding resistance is provided on the inner surface of the hole so that it can slide freely. The hole 10 of the member 9 is not a convex shape here, but an ordinary circular shape.

In the embodiment shown in FIG. 3, the entire back surface of the outer periphery of the flexible plate portion 3 of the block 2 is the block 7
It is in close contact with the surface of the block 2 side. In this case, the bending plate portion 3 may be broken when an unexpected pressure acts on the block 2.

In this case, it is advisable to make this portion have the structure shown in FIG. 1 or the structure shown in FIG. FIG. 4 is a partially modified version of that of FIG. 3, in which the flexible plate portion 3 is similar to that of FIG. Is formed by a thick circular portion 3b, and a ring-shaped comparatively low portion provided at the tip of the block 7 on the outer peripheral side of the back surface of the thick portion 3b with an inner diameter larger than the inner diameter of the thick portion 3b. The protrusion 7a was brought into close contact.

With such a structure, the thick portion 3
Although the relationship between the pressure and the strain amount changes before and after the inner peripheral edge of the back surface of b contacts the slightly concave surface inside the projection 7a of the block 7, even if a relatively large force acts, the device Will not be damaged.

[0036]

According to the present invention, the pressure measuring device is provided with the bending amount transmitting rod whose tip is in contact with the back surface of the bending plate portion formed on a part of the surface of the block, and the holder is provided on the rear side of the block. Since the deflection amount measuring plate partially supported by is placed in a state of being pressed against the rear end face of the deflection amount transmitting rod, and the strain gauge is attached to the flat portion of the deflection amount measuring plate, it is separate from the mold. It can be manufactured, and it can be easily attached to and removed from the mold, and can be easily repaired.

Further, the deflection amount measuring plate provided in the block is a flat plate, and one end portion of the plate-like deflection amount measuring plate is fixed to the holder in a cantilever manner so that the rear end face of the deflection amount transmitting rod is Since the strain gauge was attached to the deflection amount measurement plate at the base side from the position where it is in contact with the deflection amount measurement plate, the deflection amount measurement plate is in a cantilevered fixed support state, and the deflection amount is transmitted by the deflection amount transmission rod. When the measuring plate is pushed, the fulcrum does not move due to the difference in the magnitude of the force, and the strain change appears linearly.
Further, due to the simple bending strain of the beam, the strain and the amount of bending, and the pressure and pressure fluctuation in the mold can be measured and calculated reliably and easily.

Further, since the temperature compensating strain gauge is attached to the flexure amount measuring plate at the tip end side of the position where the rear end face of the flexure amount transmitting rod is in contact with the flexure amount measuring plate, the non-deformation part is used for temperature compensating. Since the strain gauge is attached, only the elongation of the flexure amount measuring plate that changes due to temperature change can be accurately measured and temperature compensation can be performed. In the past,
Since a disk-shaped bending amount measuring plate supporting the entire circumference was used and the bending amount transmitting rod was in contact with the center part, distortion occurred in all parts of the bending amount measuring plate, and for temperature compensation Although the strain gauge could not be attached, the temperature compensation strain gauge can be easily attached in the present invention.

Further, since the tip end portion and the rear end portion of the flexure amount transmission rod are tapered, the contact points with the flexure plate portion and the flexure amount measuring plate do not change or deviate, and are always Good measurement is possible. If such a pressure measuring device is used for casting using a die attached to the cavity surface of the die, as a comprehensive result of the various advantages described above, the pressure inside the die and the fluctuation of the pressure can be always ensured. It can be easily and accurately determined. For example, even when a large pressure and a small pressure of several 100 kg / cm ² alternately act on the molten metal in the cavity in a pulse shape at about 10 to 100 Hz, there is no part where resistance is generated. Since it responds quickly, the pressure fluctuation can be detected reliably and easily.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged bottom view of a portion viewed from the line AA in FIG.

FIG. 3 is a vertical sectional view showing a second embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a third embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating the operation of the conventional technique.

FIG. 6 is a vertical sectional view showing another example of the operation in the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 1a Cavity 2,7 Block 3,34 Bending plate part 5,32 Bending amount transmission rod 6,30 Bending amount measuring plate 9 Member 10 Hole 13,31 Strain gauge 14 Strain gauge for temperature compensation

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01B 7/16 G01L 19/04

Claims (10)

[Claims] 1. A flexure amount measuring plate in which a flexure amount transmission rod whose tip is in contact with the back surface of a flexure plate portion formed on a part of the front surface of the block is arranged, and a part of which is supported by a holder on the rear side of the block. Is a pressure measuring device that is configured by arranging a pressure gauge on the rear end face of the deflection amount transmission rod and attaching a strain gauge to the flat portion of the deflection amount measurement plate. 2. A flexure amount measuring plate provided in the block is a flat plate, and one end portion of the flat plate-like flexure amount measuring plate is fixed to a holder in a cantilever shape so that a rear end face of the flexure amount transmitting rod is The pressure measuring device according to claim 1, wherein the strain gauge is attached to the bending amount measuring plate at a base side of a position in contact with the bending amount measuring plate. 3. The temperature compensating strain gauge is attached to the deflection amount measuring plate at the tip end side of the position where the rear end face of the deflection amount transmitting rod is in contact with the deflection amount measuring plate. Pressure measuring device. 4. The pressure measuring device according to claim 1, wherein a central portion of the tip of the bending amount transmitting rod in contact with the back surface of the central portion of the bending plate portion is tapered. 5. The pressure measuring device according to claim 1, wherein the central portion of the rear end of the bending amount transmitting rod that is in contact with the bending amount measuring plate is tapered. 6. A flexure amount measuring plate in which a flexure amount transmitting rod whose tip is in contact with the back surface of a flexure plate portion formed on a part of the front surface of the block is arranged, and a part of which is supported by a holder on the rear side of the block. Is placed in the state of being pressed against the rear end face of the deflection amount transmission rod, and the pressure measuring device configured by attaching a strain gauge to the flat portion of the deflection amount measuring plate is installed in the stepped hole provided on the cavity side of the mold. A casting mold equipped with a pressure measuring device that is embedded and constitutes a part of the surface of the cavity of the mold with the surface of the block of the pressure measuring device. 7. A flexure amount measuring plate provided in the pressure measuring device is a flat plate, and one end of the flat plate-like flexure amount measuring plate is fixed to a holder in a cantilever shape, and the flexure amount transmitting rod A casting mold provided with the pressure measuring device according to claim 6, wherein a strain gauge is attached to the bending amount measuring plate at a base side of a position where the end face is in contact with the bending amount measuring plate. 8. The temperature compensating strain gauge is attached to the deflection amount measuring plate at the tip end side of the position where the rear end face of the deflection amount transmitting rod is in contact with the deflection amount measuring plate. A casting mold equipped with a pressure measuring device. 9. A casting equipped with the pressure measuring device according to claim 6, wherein the central portion of the tip of the bending amount transmitting rod in contact with the back surface of the central portion of the bending plate portion is tapered. Mold. 10. A casting metal having a pressure measuring device according to claim 6, wherein a central portion of the rear end of the bending amount transmitting rod that is in contact with the bending amount measuring plate is tapered. Type.